The core project will fulfill two functions, to carry out chemical analysis for the other projects and to improve existing analyses as required. Congener specific PCB analysis is carried out by gas chromatography (gc) on phenyl methyl silicone bonded fused silica capillaries with electron capture (ec) detection. Seventy-one peaks are measured; 68 contain PCB congeners, the remainder are HCB, p,p'-DDE and mirex, widespread Lake Ontario pollutants. Congener specific TCDD and TCDF analysis ( > 4 chlorine substituents) is carried out using heavy isotope-labelled standards representing each isomer group by gas chromatography with high resolution mass spectral detection (VG Autospec Q). PCB congener identification will be confirmed using a second gc column (SB-octyl-50) and also by gc with a mass selective detector (MSD) in tandem with a Fourier transform infra red detector (IRD) which will also be employed for PCB degradation product identification. Mono-ortho-substituted and non-ortho- substituted PCB (coplanar PCB) will be determined using gc/ec followed by separation from di- through tetra-o-substituted by carbon chromatography. Polynuclear aromatic hydrocarbons (PAH or PNA) will be determined by gc/MSD using heavy isotope labelled standards for each isomer group. Method improvements will include carbon separation for coplanar PCB which will be automated using either activated carbon or Hypercarb HPLC chromatography. Urine will be further evaluated as a sampling fluid for PCB monitoring. Physicochemical discrimination of PCB congeners during aqueous dissolution and during co-precipitation from water will also be investigated.